/*
 * pid.c PID controller for testing cooling devices
 *
 *
 *
 * Copyright (C) 2012 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 or later as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Author Name Jacob Pan <jacob.jun.pan@linux.intel.com>
 *
 */

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <sys/types.h>
#include <dirent.h>
#include <libintl.h>
#include <ctype.h>
#include <assert.h>
#include <time.h>
#include <limits.h>
#include <math.h>
#include <sys/stat.h>
#include <syslog.h>

#include "tmon.h"

/**************************************************************************
 * PID (Proportional-Integral-Derivative) controller is commonly used in
 * linear control system, consider the the process.
 * G(s) = U(s)/E(s)
 * kp = proportional gain
 * ki = integral gain
 * kd = derivative gain
 * Ts
 * We use type C Alan Bradley equation which takes set point off the
 * output dependency in P and D term.
 *
 *   y[k] = y[k-1] - kp*(x[k] - x[k-1]) + Ki*Ts*e[k] - Kd*(x[k]
 *          - 2*x[k-1]+x[k-2])/Ts
 *
 *
 ***********************************************************************/
struct pid_params p_param;
/* cached data from previous loop */
static double xk_1, xk_2; /* input temperature x[k-#] */

/*
 * TODO: make PID parameters tuned automatically,
 * 1. use CPU burn to produce open loop unit step response
 * 2. calculate PID based on Ziegler-Nichols rule
 *
 * add a flag for tuning PID
 */
int init_thermal_controller(void)
{
	int ret = 0;

	/* init pid params */
	p_param.ts = ticktime;
	/* TODO: get it from TUI tuning tab */
	p_param.kp = .36;
	p_param.ki = 5.0;
	p_param.kd = 0.19;

	p_param.t_target = target_temp_user;

	return ret;
}

void controller_reset(void)
{
	/* TODO: relax control data when not over thermal limit */
	syslog(LOG_DEBUG, "TC inactive, relax p-state\n");
	p_param.y_k = 0.0;
	xk_1 = 0.0;
	xk_2 = 0.0;
	set_ctrl_state(0);
}

/* To be called at time interval Ts. Type C PID controller.
 *    y[k] = y[k-1] - kp*(x[k] - x[k-1]) + Ki*Ts*e[k] - Kd*(x[k]
 *          - 2*x[k-1]+x[k-2])/Ts
 * TODO: add low pass filter for D term
 */
#define GUARD_BAND (2)
void controller_handler(const double xk, double *yk)
{
	double ek;
	double p_term, i_term, d_term;

	ek = p_param.t_target - xk; /* error */
	if (ek >= 3.0) {
		syslog(LOG_DEBUG, "PID: %3.1f Below set point %3.1f, stop\n",
			xk, p_param.t_target);
		controller_reset();
		*yk = 0.0;
		return;
	}
	/* compute intermediate PID terms */
	p_term = -p_param.kp * (xk - xk_1);
	i_term = p_param.kp * p_param.ki * p_param.ts * ek;
	d_term = -p_param.kp * p_param.kd * (xk - 2 * xk_1 + xk_2) / p_param.ts;
	/* compute output */
	*yk += p_term + i_term + d_term;
	/* update sample data */
	xk_1 = xk;
	xk_2 = xk_1;

	/* clamp output adjustment range */
	if (*yk < -LIMIT_HIGH)
		*yk = -LIMIT_HIGH;
	else if (*yk > -LIMIT_LOW)
		*yk = -LIMIT_LOW;

	p_param.y_k = *yk;

	set_ctrl_state(lround(fabs(p_param.y_k)));

}
nge='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Thomas Gleixner &lt;tglx@linutronix.de&gt;</td><td class='right'>2017-01-31 09:37:34 +0100</td></tr>
<tr><th>committer</th><td>Thomas Gleixner &lt;tglx@linutronix.de&gt;</td><td class='right'>2017-01-31 21:47:58 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/wireless/sysfs.c?id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>0becc0ae5b42828785b589f686725ff5bc3b9b25</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/wireless/sysfs.c?id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>be6d0e1f37c38ed0a7dd5da2d4b1e93f0fb43101</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/wireless/sysfs.c?id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>net/wireless/sysfs.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/wireless/sysfs.c?id=24c2503255d35c269b67162c397a1a1c1e02f6ce'>24c2503255d35c269b67162c397a1a1c1e02f6ce</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/wireless/sysfs.c?id=0becc0ae5b42828785b589f686725ff5bc3b9b25&amp;id2=24c2503255d35c269b67162c397a1a1c1e02f6ce'>diff</a>)</td></tr></table>
<div class='commit-subject'>x86/mce: Make timer handling more robust</div><div class='commit-msg'>Erik reported that on a preproduction hardware a CMCI storm triggers the
BUG_ON in add_timer_on(). The reason is that the per CPU MCE timer is
started by the CMCI logic before the MCE CPU hotplug callback starts the
timer with add_timer_on(). So the timer is already queued which triggers
the BUG.

Using add_timer_on() is pretty pointless in this code because the timer is
strictlty per CPU, initialized as pinned and all operations which arm the
timer happen on the CPU to which the timer belongs.

Simplify the whole machinery by using mod_timer() instead of add_timer_on()
which avoids the problem because mod_timer() can handle already queued
timers. Use __start_timer() everywhere so the earliest armed expiry time is
preserved.

Reported-by: Erik Veijola &lt;erik.veijola@intel.com&gt;
Tested-by: Borislav Petkov &lt;bp@alien8.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanos
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>Diffstat</a> (limited to 'net/wireless/sysfs.c')</div><table summary='diffstat' class='diffstat'>